An accused Mafia leg-breaker-turned-born-again author wasn’t exactly Christian when he gleefully bragged to a pal about a 1992 rubout, the former buddy testified.

Mob snitch John “Big John” Mamone, 61, told jurors at the Bronx trial of alleged rubout getaway driver Paul “Doc” Gaccione, 65, that the now-holy-rolling writer was “all excited” when he picked Mamone up from JFK Airport in ’92.

“Buddy, you should have been there,” Mamone said Gaccione giddily told him several days after Gaccione allegedly helped John “Johnny Balls” Leto assassinate Angelo Sangiuolo for sticking up several mob-run gambling joints.

“We did ‘a piece of work,’ ” Gaccione allegedly bragged to Mamone, referring to a term where up-and-coming gangsters earn mob points with their bosses in hopes of becoming “made” family members.

Since being jailed, Gaccione has penned an autobiography, “Beyond the Beyond: My Journey to Destiny,” in which he claims he speaks to the dead, has viewed the hereafter and witnessed miracles.

Mamone’s testimony was the second blow to Gaccione in less than two weeks.

Last week, Gaccione’s former slay pal-turned-snitch Leto detailed how he and Gaccione took Sangiuolo for a short ride before shooting him in the chest and head.

Gaccione’s lawyer, Michael Torres, accused Mamone of seeking an early jail release in exchange for his testimony — even though Mamone’s already served 12 years for racketeering and conspiring to distribute marijuana.